It is known that a flight plan generally comprises waypoints that the aircraft must overfly, information (altitude, speed, etc.) pertaining to these waypoints, as well as information relating to legs between the various waypoints. Such a flight plan makes it possible to construct a flight trajectory comprising said legs, generally rectilinear, which join up laterally with said waypoints. Said flight trajectory comprises a lateral trajectory defined in the horizontal plane and a vertical trajectory (flight profile) defined in the vertical plane.
It is known moreover that the revision of a flight plan can consist in deleting or adding waypoints, in modifying the position of waypoints or of characteristics (time, speed, altitude) pertaining to these waypoints or to said legs.